What kinds of assessments can we as teachers do to figure out what our students already know about language and where we should start teaching it?

We have read several strategies that would give us as teachers a starting point for teaching language. One of the best assessments is having the students do some sort of writing at the beginning of a new class to determine where they stand as writers. For example, you could use an activity similar to the one we did at the beginning of this class, a letter to the teacher. By having the students write a letter to the teacher, the teacher can see the students' style of writing, their techniques, and areas of struggle that may need some work. A teacher can tell where their students are in their exploration of language by having them present a piece of language to be assessed. A formal test or quiz isn't needed and that's refreshing!